redletterdave writes: "Scientists have created a lithium-ion battery that can stretch up to 300% of its original size and still function. After years in development, Yonggang Huang of Northwestern University and John A. Rogers of University of Illinois demonstrated how their battery invention can consistently power a commercial LED, even when twisted, folded and contorted around a human elbow. The stretching process is reversible so manufacturers won't need to worry about bending the battery out of shape, and the battery itself — with its 8-9 hour life — can be charged wirelessly, meaning it can be used anywhere, including inside the human body."